ゴム弾性式によるポリウレタンエラストマーの応力 : ひずみ挙動解析

Abstract

The new rubber elastic equation derived from an uniform stress hypothesis was applied in order to analyze the stress-strain curves of polyurethane elastomers. Good applicability of the presented equation for many experimental data was obtained for both the extension and the retraction curve of hysteresis cycles as well as the ordinary bulk rubber vulcanizates. The parameters, such as vkT, b, C_1 and C_2 are obtained from this plot and Mooney-Rivlin plot. The proportional relationship was obtained between vkT and C_1,b and C_2,respectively. In the case of one-shot type polyurethane, these parameters increased with increasing the concentration of urethane linkage. On the other hand, for millable type polyurethane, vkT and C_1 increased, and b and C_2 decreased with increasing of the crosslinking density. Under elevated temperaure, the values of b and C_2 become small. The apparent activation energy obtained from the Arrhenius plot was within the value of 3∿5kcal/mol. From these results, it can be considered that b and C_2 are the parameters concerned with internal viscous flow. The stress-strain curve of polyurethane elastomers modifided by the addition of vinyl monomer was analyzed with our proposed elastic equation and Mooney-Rivlin equation. As the results, vkT and C_1 concerned with primaly linkage has become high values by the addition of vinyl monomers. While, b and C_2 arising from the weak secondary linkage decreased with increasing the amount of the vinyl monomers. Furthermore, the temperature dependency of b and C_2 with respect to the polymer blended one. These results suggested that the vinyl monomers were blocked with the polyether segment at the stage of polyurethane formation.